The term “workload” designates a measurable physical quantity that enables the computing of the occupancy rate of an information technology resource exploited by the transaction server to execute the processing required by the terminal. Each information technology resource possesses a load threshold beyond which it can no longer be used to perform additional processing. When this load threshold is crossed, then the resource or system that incorporates this resource is said to be “overloaded.” The occupancy rate is typically the ratio between the number of already ongoing processing operations and this load threshold. For example, typically, the measurable physical quantity is the number of simultaneous connections currently set up with the server. This measurable physical quantity can also be the number of operations executed per second by an electronic microprocessor of the server to process the requests from the terminals.
Smoothing the workload of the transaction server consists, first of all, in preventing its load threshold from being crossed at points in time. Typically, when the load threshold is reached, either the connection server rejects any new connection or the server sets up the new connection but does not execute the processing operation requested by the terminal because the necessary resource or resources are overloaded. In both these cases, there is deemed to be a “failure” of the connection since it has not led to the immediate execution of the processing requested by the terminal.
Preferably, the smoothing of the workload also consists in distributing the processing operations executed by the transaction server as uniformly as possible in time, and, if possible, in maintaining the workload constantly above a predetermined threshold.
To smooth the workload of the transaction server, prior-art methods include: computing a scheduled date on which the terminal must set up a connection with the transaction server to transmit a request to it, activating the setting up of this connection by this terminal according to the computed scheduled date so that the setting up of this connection takes place only when or after this scheduled date has arrived, and building a workload schedule for the transaction server according to the scheduled dates computed, this workload schedule associating, with each possible date, a forecast workload of this transaction server at this date.
The term “date” designates any piece of information used to indicate a determined instant relatively to a point of origin of the times. A date can take different formats. For example, one of the classic formats is the year/month/date/hour/minute/second format. The date can also be written in the form of a digital value or a number of successive predetermined time intervals that have elapsed since the point of origin of the times. The point of origin of the times is generally absolute and common to all the terminals and servers. However, the point of origin of the times can also be fixed relative to a particular event, such as the reception of a summons message. For example, here below in this description, the date is an instant measured by the number of seconds that have elapsed since a point of origin of the times common to all the apparatuses. The clocks used by the different apparatuses to measure the date are synchronized with one another in a conventional manner.
Here below, the term “current date” denotes the date corresponding to the present instant.
Among the known methods is that envisaged in the patent application JP 2007 005971 to fix the scheduled date according to the workload schedule of the transaction server to limit connection failures on the scheduled date. As a result of this, the workload of the transaction server is smoothed efficiently since, in principle, the terminal is connected to the transaction server only on a date when this server has the capacity to execute the requested processing operation. This limits overloads on the transaction server. However, it is desirable to improve this method to smooth the workload of the transaction server even more efficiently.
The prior art is also known from: EP 1566736, and U.S. Patent Publ. 2008/154805.